Tailstock lock



Jan. 23, E945. w. M, MCCONNELL.

TAIL STOCK LOCK 2 sheets-sheet 1 Filed Aug. 14, 1943 IVN E, .JAN N @NNN @Nur QN. m f TV v m m Q v WWW N! Mmmfnwllwhndl. www.

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2 Sheets-Sheet 2 Patented Jan. 23, 1945 unirse STATES PATENT OFFICE 2,368,032 TAILSTOCK LOCK WilliamM. McConnell, McKeesport, Pa., assigner to Mackintosh-Hemphill Company,v Pittsburgh Pa.,` a corporation of Delawar Application August 14, 1943-, Serial, No. 498,691

(ci. :z2-sn 8 Claims.

This invention relates to tail-stock clampingl devices, especially those that are useful vin heavy duty engine lathes wherein the thrust exerted upon the tail-stock is great, which necessitates the use of means of great strength and holding power to secure the tail-stock against accidental displacement during operation of the lathe.

The common, or conventional, structure of en gine lathes comprises as elements a face-plate which is mounted and rotatably driven at a headstock which provides driving connections for the face-plate a center-post carried by the face-plate and providing a live center for the work;I and a tail-stock mounted in the lathe bed and including a static center for the work in opposition to the live center carried by the face-plate. The tailustock, with its static-opposed center, conventionally is adjustable across the lathe bed for accurate alignment with the live center which is carried by the head-stock of the lathe.

adjustable longitudinally of the lathe bed toward and away from the live center to. bring its center functionally into opposition on the work.

One primary object of my invention isto provide in association with the tail-stock ,of an engine lathe, a clamping assembly which so sturdy and eifectve that it is capable of sustaining heavy loads and is capable of clamping the tail-stock securely to the bed of the lathe in accurate alignment with the live center carried by the face-plate.

Another object of the invention is to provide a clamping organization for the base structure of a lathe tail-stock such that the elements acted' upon in loosening and tightening clamping engagement are easily accessible, and s uch that none of these elements need be removedfrom assembly in making adjustment of the tail-stock.y

Another object of my invention is to provide a clamping assembly of that identied sort which functions eiectively, without requiring any spe cialized structure or form of the lathebed to which it clamps the tail-stock.

In the accompanying drawings:.

Fig. I is a vertical longitudinal sectional view through the tail-stock of an engine lathe and the mounting structure therefor, showingthe novel clamping assembly of my invention.

Fig. II is a rear view of the tail-stock assemblyv The base in which the tail-stock is thus mounted vvis y Fig. III is. a detail perspective *viewA of one pressurel member of the clamping assembly.

Fig. IV is a detail perspective view of the other pressure member ofthe clamping assembly.

Fig. V is a detail perspective view of a clamping; member, cooperative- With the pressure members of FigsIII and Describing the drawings in detail, the lathe bedincludes two transversely spaced, horizontal side railsv lf' and 2, having top surfaces 3 which form waysl for slidably supporting the tail-stock, vertical facing surfaces 4 and bottom surfaces 5-.. All of' these surfaces are machined to smooth planes. arranged in accurately spaced and correct angular relation. The tail-stock assemblyV of the lathe includes a base- 61 having longitudinally spaced' pairs of' supporting surfaces 'l that rest slidably on the upper surfaces 3 of the side rails. Base E' has portions' 8 which extend downwardly between the transversely spaced side rails of the lathe bed'. The downwardly extended portions 8: have vertical surfaces 9, arranged to contact and bear against the opposed vertical surfaces' 4: of the rails. f l

In order tol clamp the tail-stock base rigidly, both transversely andv longitudinally of the lathe, so that. alignment of the tail-stock center with the live center'of the head-stock may be maintained accurate when the lathe'is working, I have provided an assembly `for clamping the tail-stock base in a transverse direction against -the vertical surfaces 4 of one of the rails. The

downward extensionsy 8 of the tail-stock base carry twor clamping members IU that may be formed integral with the base, but which are preferably attached blocks, as shown, that are set into the base and secured as by bolts H. The pair of clamping members I0 are placed one at each end of the tail-stock base, and are both acted upon by a pair of'longitudinally extended pressure v bars.

tudinally of the lathe bed in cooperative relation with the clamping members l0 and the side rails ll and 2f. 'Pressure bar I6, one of the duplicate ends of which is shown, isformed in each of its' end regions inl whichy it rcooperates with vvone-of the 'clamping members'l, with oneup'- wardly and outwardly beveled side surface I3. The other side surface in 'each of the end regions of the pressure bar I6 has a rectangular chamfer I9 at its upper edge. In each of its end regions the pressure bar is pierced by a bolt hole 26. As shown in Fig. III pressure bar I6 is cut in between its end regions along one side of the bar, and it is to be understood that it may similarly be cut in between end regions at the other side of the bar. Because the contact surfaces of the pressure bar are needed only in its end regions, the elimination of metal between those regions lessens the weight of the bar and economizes material.

The other pressure bar I1 has rectangular chamfers 2| and 22 extended along its upper side edges. The structure of this pressure bar, also, may be cut away between end regions which cooperate with the two clamping members I at the ends of the tail-stock base. This may be done to eliminate at least the chamfered structure of the pressure bar between its end regions, with consequent decrease in weight and saving in material. In each end region of the pressure bar there is an elongate bolt hole 23 arranged with its major axis extended transversely of the pressure bar.

In assembly the end regions of the pressure bars are brought into cooperative relation with the two clamping members ID, the organization of these elements being shown clearly in Fig, II of the drawings. In such organization the pressure bars I6 and I'I are adjustably supported respectively by two pairs of king bolts 24 and 25, which pass through the tail-stock base and the bolt holes 20 and 23 of the pressure bars and the heads of which bear against the under surfaces of the pressure bars. As so supported the upwardly and outwardly chamfered faces in the end regions of pressure bar IB cooperate with the inwardly declining contact surfaces I3 of the clamping members I0, and the`chamfered regions I9 of the pressure bar engage the corner of one side rail I at the junction of its side face 4 and bottom face 5. The other pressure bar Il has its charnfered regions 2| underlying the clamping members I0 in their chamfers I5, and has its other chamfered regions 22 embracing the inwardly presented side face 4 and bottom face 5 ofl the second side rail 2.

Fig. II of the drawings shows the tail-stock base clamped to the lathe bed. To bring the clamping assembly into that condition it is necessary merely to tighten up on nuts 24a and 25a, which are threaded on the Shanks of bolts 24 and 25 and bear through washers upon the upper surface of bottom plate 26 of the tail-stock structure. This action, which is had on all the four king bolts, draws both ends of both the pressure bars I6 and I1 upward, and forces the surfaces in their chamfered regions into rm engagement with the under surfaces 5 of that one of the side rails I and 2 which respectively stands adjacent each pressure bar. Also upward movement of pressure bar I6 causes its sloping contact surfaces I8 to move cooperatively with the sloping contact surfaces I3 of the clamping members I0. This cooperative eifect propels the tailstock base as a whole away from the side rail I to which the pressure bar I6 is adjacent, and toward the other side rail 2 until the vertical surfaces 9 on extensions 8 of the tail-stock base are forced rmly against vertical surfaces 4 of the side rail. The tail-stock base is thus clamped to the lathe bed by pressure of the pressure bars I6 and I1 upwardly against the under surfaces of the side rails I and 2, and the tail-stock base itself is forced firmly against the side rail 2. Desirably the downward extensions 8 of the tailstock base have a loose t between the siderails I and 2, with merely enough clearance between the side surfaces 9 and the vertical Contact surfaces of the side rails to permit the tail-stock structure as a whole, to slide on the rails in making adjustments of the tail-stock longitudinally of the lathe bed. Slight tightening action oi nuts 24a and 25a on the bolts 24 and 25 is therefore adequate to exert a great clamping force on the tail-stock base, holding it in fixed position against the operating forces of the lathe.

It is possible to resolve each of the pressure bars into two clamping blocks, each cooperative with one of the clamping members I0. There is advantage, however, in utilizing pressure bars which provide continuous structures extended between the clamping members. This is for the reason that the bolts at the opposite ends of the tail-stock base frequently are not drawn up at exactly the same instant of time. The physical continuity of vthe pressure bars counteracts the tilting tendency which otherwise results from lack of absolute synchronism in drawing-up at the opposite ends of the tail-stock base. If desired, the two clamping members IIJ may be resolved into a single structure continuous from end to end of the tail-stock base, and such modification is indicated if the tail-stock base is relatively short. As a refinement, the bolts 24 have their heads tapered as at 28 to t -cooperatively tapered seats in the underbody of pressure bar I6. This tends to give a direct upward pull on the pressure bar in drawing-up on the bolts.

Transverse adjustment of the tail-stock is made without disturbing the clamped engagement of the tail-stock base with the lathe bed. As appears in Fig. II of the drawings, the bolts 24 and 25 pass through transversely elongate holes 29 in the bottom plate 26 of the tail-stock structure, so that this structure may be moved on the tail-stock base 6 and may be clamped in adjusted position by suitable elements associated with it.

Adjustment of the tail-stock base, and the tailstock carried by it, longitudinally of the lathe bed is permitted by retracting nuts 24a and 25a on the bolts 24 and 25. This permits the pressure bars I6 and Il to drop away from the under surfaces of the side rails I and 2 the distance permitted by increased extension of the bolts 24 and 25 below the bottom of the tail-stock base, and frees the `clamping members ID from the forcing action of pressure bar I6. The clamping effect which locks the tail-stock base to the lathe bed is thus released and longitudinal movement of the base is made possible. It is to be noted that release of the clamping effect and its subsequent restoration does not involve the removal and replacement of any element of the clamping assembly, but that all elements of the clamping assembly are loosened, or freed, while leaving them in their assembly relation and in condition to be again brought into their clamping engagements. This advantage is of great vvalue in association with the tail-stock of an engine lathe, because the removal and replacement of parts within the rigidly confined space embraced in the lathe bed would present a problem of major importance. It is to be noted, also that in the organization all beveled and chamfered surfaces are carried by the-smaller elements of the clamping assembly, thus avoiding the diiculty involved in beveling and chamfering the side rails of the lathe bed. The combination of the forces directed both upwardly and transversely against the side rails of the lathe bed gives a clamping effect of particular firmness which,- ,together with thestructural strength of the elements involved in the clamping, holds the tail-stock accurately in position against the exertion of the forces which are encountered in operation of a heavy duty engine lathe.

Several structural modifications have been above suggested. It is to be understood that those and various other modifications may be made while remaining Within the scope ofrmy invention as dened in the appended claims.

I claim as my invention:

1. In combination with a lathe bed having parallel spaced side rails and a tail-stock base mounted between the said side rails for movement along the lathe bed, a clamping assembly including a clamping member dependent from the tail-stock base, a pair of through-bolts extended through the tail-stock base, pressure members carried through-bolts in position each to underlie respectively the said clamp-ing member and one of the side rails of the lathe bed, one of the said pressure members and the said clamping member having cooperatively beveled lateral faces, so that pressure exerted by the said through-bolts forces the pressure members of the assembly against the under faces of both the said side rails and forces the tailstock base laterally against one of the said side rails.

2. In combination with ra lathe bed having parallel spaced side rails and a tail-stock base mounted between the said side rails for movement along the lathe bed, a clamping assembly including a clamping member dependent from the tail-stock base, a pair of through-bolts extended through the tail-stock base, pressure members carried respectively by the said through-bolts in position each to underlie the said clamping member and one of the side rails of the lathe bed, both the said pressure members being formed t@ have a square-shouldered engagement each with one of the said side rails, one of the said pressure members and the said clamping member having cooperatively beveled lateral faces, so that pressure exerted by the said through-bolts forces the pressure members of the assembly against the under faces of both the said side rails and forces the tail-stock base laterally against one of the said side rails.

3. In combination with a lathe bed having parallel spaced side rails and a tail-stock base mounted between the said side rails for movement along the lathe bed, a clamping assembly comprising a clamping member dependent from the said tail-stock base and having a beveled lateral face, a separate pressure member having a lateral face cooperatively beveled with respect to the beveled lateral face of the said clamping member and underlying one side rail of the lathe bed, and means organized with the said separate pressure member to force the said member upwardly against the side rail which it underlies and by the cooperation of its b-eveled lateral face with the beveled lateral face of the clamping member to force the tail-stock base laterally against the other side rail of the lathe bed.

4. In combination with a lathe bed having parallel spaced side rails and a tail-stock base respectively by the said mounted between the said side rails -for movement along the lathe bed, a clampingassembly comprising a clamping member dependent from the said tail-stock base andk having a beveled lateral face, a separate pressure member having a lateral face cooperatively beveled with respect to the beveled face of the said clamping member and underlying one side' rail of .the lathe bed, means `organized with the said separate pressure member to force thatfmember upwardly against the side rail which it underlies and by the cooperation of its beveled face with the beveled face o-f 'the clamping member to force the tail-,stock base laterally against the other side rail of the lathe bed, and a second pressure member mounted and arranged to be lforced upwardly against the said last-.named side rail.

5. In combination with a lathe bed having parallel spaced side rails and a tail-stock base mounted between the said side rails for movement along the lathe bed, a clamping assembly comprising two laterally beveled clamping members dependent from the tail-stock.- base and spaced from each other longitudinally of the tail-stock, a separate pressure bar extended longitudinally of the tail-stock having a lateral face beveled cooperatively with the cooperative lateral bevels of the said clamping members and underlying one side rail of the lathe bed, and means organized with the said separate pressure bar to force the said member upwardly against the side rail which it underlies and by the cooperation of its beveled lateral face with the lateral bevels of the clamping members to force the tail-stocl base laterally against the other side rail of the lathe bed.

6. In Icombination with a lathe -bed having parallel spaced side rails and a tail-stock base mounted between the said side rails for movement along the lathe bed, a clamping assembly comprising two laterally beveled clamping members dependent from the tail-stock base and spaced from each other longitudinally ofthe tail-stock, a 4separate pressure bar extended longitudinally of the vtail-stock having a lateral face beveled cooperatively with the cooperative lateral bevels of the said clamping members and underlying one side rail of the lathe bed, means organizedwith the said separate pressure bar to force the said memberupwardly against the side rail which it underlies and by the cooperation of its beveled lateral face with the lateral bevels of theuclamping members to force the tail-stock base laterally against the other side rail of the lathe bed, a second pressure bar underlying both the said clamping members, and means organized to force the said second pressure bar upwardly against that side rail against which the tail-'stock base is forced.

7. In combination with a lathe bed having.

parallel spaced side rails and a tail-stock base mounted between the said rails. for movement along the lathe bed, a clamping assembly comprising clamping structure dependentl from the tail-stock base and presenting toward one of the force the said member upwardly against the side rail which it underlies and by the cooperation of its beveled lateral face with the lateral beveled faces of the said clamping structure to force the tail-stock base laterally against the other side rail of the lathe bed.

8. In combination with a lathe bed having parallel spaced side rails and a tail-stock base mounted between the said rails for movement along the lathe bed, a clamping assembly comprising clamping structure dependent from the tail-stock base and presenting toward one of the said side rails two beveled lateral faces spaced from each other longitudinally of the tail-stock, a separate pressure bar extended longitudinally of the tail-stock having a lateral face beveled cooperatively with the cooperative lateral bevels of the said dependent clamping structure and underlying one Side rail of the lathe bed and abutting one edge thereof, means organized with the said separate pressure bar to force the said member upwardly against the side rail which it underlies and by the cooperation of its beveled lateral face with the lateral beveled faces of the said clamping structure to force the tail-stock base laterally against the other side rail of the lathe bed, a second pressure bar underlying the said dependent clamping structure, and means organized to force the said second pressure bar upwardly against that side rail against which the tail-stock base is forced.

WILLIAM M. MCCONNELL. 

